Yep, I’ve seen that exact split, and it’s usually not that the deep end is “dirtier,” it’s that it’s behaving like a different pool.
Deep water mixes way less than people think. The top warms up, gets good circulation, and looks perfect. The bottom stays cooler and slower, so fine particles and even slightly unbalanced water just hang there. That bluish haze is often microscopic stuff that never makes it up to the skimmer. I noticed it on mine when I brushed the deep end and a cloud would bloom but never fully clear unless I forced the water down there.
A big tell is whether your main drain is actually pulling. A lot of systems barely use it, so the deep end becomes a dead zone. When I checked, my skimmer was doing almost all the work and the drain was barely moving water. After I adjusted valves to give the drain more suction and aimed one return almost straight down the slope, the haze finally stopped coming back.
Also worth checking temp difference. If the deep end feels noticeably colder, you’re probably dealing with layering. Long run times don’t always fix that unless the flow pattern actually breaks the layers. Brushing toward the drain and changing return direction did more for me than shocking ever did. Anyone ever check how much suction their main drain is really getting?
